The application filed with the U.S. Patent and Trademark Office in June 2011 covers technology for "on-demand generation of electricity from stored wind energy."

Standard wind turbine designs use wind energy along its blades (or sails) to turn rotors, which power machinery or electric generators. But Apple's proposal offers a twist - one that accounts for the variability of wind.

In its systeme, the rotational energy created by the turbine is to generate heat that is then stored in a "low-heat-capacity" fluid. The heat is then transferred into a working fluid that creates steam, which is used to power an electric generator.